7875 + 5.9 + E85 + Megasquirt

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subcom said:
50/50 water/meth
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I’d ditch the water at your power level. It’s not doing you any good and is taking up space. You will not be able to get enough fuel in the chamber when you’re spraying that much water. It also screws with the number your wideband will show.
 
TT5.9mag said:
I’d ditch the water at your power level. It’s not doing you any good and is taking up space. You will not be able to get enough fuel in the chamber when you’re spraying that much water. It also screws with the number your wideband will show.
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I can ramp it in and PWM the amount delivered. It doesn’t have to be an all or nothing with the WM. I’m just looking at it as extra insurance when ambient temp is really high and IATs start to climb.
 
subcom said:
I can ramp it in and PWM the amount delivered. It doesn’t have to be an all or nothing with the WM. I’m just looking at it as extra insurance when ambient temp is really high and IATs start to climb.
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Yea I know you’ve got all the control in the MS but you’re still putting a non burnable in the chamber. The water definitely evaporates and cools the charge but at some point (you’re there now) you start to fight being able to tune around the water.
 

Falling on its face right out of the hole. I think I had the WM enabled on this run.
 
Tore the front of the engine off to replace a leaking front seal and found some funny stuff. Pin from the timing chain tensioner worked its way forward and wore a hole in the timing chain cover. Discovered the elastometer in my harmonic balancer is worn out also. Might explain how my crank sensor got trashed.
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Nobody makes a nice SFI balancer for these crankshafts so I ordered another one similar to this one.
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Nice catch. That could’ve gotten bad. You going to toss the tensioner in the garbage? :poke: I think PRW and Blueprint engines are both making dampers now for magnums. PRW is sfi rated. Not sure on the blueprint one yet.
 
TT5.9mag said:
Nice catch. That could’ve gotten bad. You going to toss the tensioner in the garbage? :poke: I think PRW and Blueprint engines are both making dampers now for magnums. PRW is sfi rated. Not sure on the blueprint one yet.
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I ordered the Blueprint one. It’s not SFI rated and looks just like the PRW it’s replacing. I’m sure they’re the same part. The tensioner I’m not touching. It’s still doing its job. Not sure what the purpose of that little pin was.
 
E85 Plug reading thoughts? Fresh Autolite 3922s, gapped 0.028. Same plug I’ve used for several years.

- 3rd gear pull, WOT about 11psi max,
- 22 degrees, 11.00AFR (gas scale).
Killed the engine immediately after the pull. No idle, no cruise.

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Plug looks good. Cut the shell off of one so we can see the fuel ring. E85 is harder to read and you’re spraying meth on that which makes it even more difficult. But I can tell you you’re not too rich. The timing is super safe though. You’re not even starting to put heat in the strap. I’d use a step colder plug
 
TT5.9mag said:
Plug looks good. Cut the shell off of one so we can see the fuel ring. E85 is harder to read and you’re spraying meth on that which makes it even more difficult. But I can tell you you’re not too rich. The timing is super safe though. You’re not even starting to put heat in the strap. I’d use a step colder plug
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Thanks. I’m staying off the meth for now, lol. Ambient temps are lower now and IATs are generally pretty sane. I hope to make it to the track this Friday. Going to bump the timing a couple degrees and see how it responds.
 
subcom said:
Thanks. I’m staying off the meth for now, lol. Ambient temps are lower now and IATs are generally pretty sane. I hope to make it to the track this Friday. Going to bump the timing a couple degrees and see how it responds.
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When you do that use a new plug and compare it to an old one. You don’t need to replace the whole set though. Just one. Maybe you can cut that one open.
 
Second and last pass. I think this is my PB on the ET. 22.9psi. I had the boost cut set to 23psi and it killed the motor about 50’ before the stripe which is probably reflected in the MPH. I put the 2nd spring in my wastegate which gives it a baseline of 10psi. I’m having to recalibrate and learn how boost duty impacts overall boost numbers. My first run was 50% duty cycle, second was 60%.
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The HP calc says I’m producing about 725hp at the flywheel at 112mph. Seems about right. Looking at my logs I think I might be reaching the law of diminishing returns on this setup. From 18psi to 23psi I pick up a couple MPH but overall ET is about the same. I’m also riding the shift light pretty much the entire pass. Either the converter is slipping or the trans is. Not sure adding more boost will gain much. Probably pop these Felpro head gaskets but it’s been a super solid build so far. I did a compression test and everything looks great on all eight. Oil pressure still good. Motor seems to be healthy with many more miles and passes available in it.

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Log from my 2nd pass. Only got 2 in that night. Track was a mess. There was a wreck, a bunch of cars threw down liquid...wasn't a productive night. I made almost 23psi on this one before boost safety kicked in. Boost back pressure is still really good (about 29psi) so I think this turbo is right-sized for the combo. IAT/MAT is getting up there (162F) though and I haven't been using the water/meth injection to cool it down and this was on a cool 69F night.

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18 to 23 is a pretty big swing in boost for it to not pick up. Even at 10hp/pound which is conservative. I’d say you definitely have a slipping trans or you’re driving through the converter.
 
Nice runs! I agree you’ve got a trans/converter issue. Should be PLENTY left in that turbo. Did injector duty cycle increase with the increase in boost? I would be curious to see what rpm logs show for your shifts.
 
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turbovan said:
Nice runs! I agree you’ve got a trans/converter issue. Should be PLENTY left in that turbo. Did injector duty cycle increase with the increase in boost? I would be curious to see what rpm logs show for your shifts.
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Duty cycles climbs from 10% at launch until 67% at the end of the run. It's hard to see rpm drop during the shifts. There is a spike to 6500 and drop to 6000 where the 2-3 should have happened but it could have been wheel spin or the trans slipping. I don't have an easy way to log shifts in the Megasquirt but I'm sure it could be done with some kind of output on the shifter.
Not sure what my next move is. I wanna go faster. I'm teetering between pulling this whole platform out and throwing in an LS or dumping a bunch of money into this 727 to give it a trans brake and necessary upgrades to support that.
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subcom said:
Duty cycles climbs from 10% at launch until 67% at the end of the run. It's hard to see rpm drop during the shifts. There is a spike to 6500 and drop to 6000 where the 2-3 should have happened but it could have been wheel spin or the trans slipping. I don't have an easy way to log shifts in the Megasquirt but I'm sure it could be done with some kind of output on the shifter.
Not sure what my next move is. I wanna go faster. I'm teetering between pulling this whole platform out and throwing in an LS or dumping a bunch of money into this 727 to give it a trans brake and necessary upgrades to support that.
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You need a converter
 
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